Landing indicator for airports



Oct. 5, 1937. A. M. l gm ET AL 2,095,208

LANDING INDICATOR FOR AIRPORTS Fild may 6, 1951 10 Sheets-Shet 1' 0a. 5, 1937. A. M. WILHELM ET AL LANDING INDICKIOR FOR AIRPORTS Filed fla 6. 19s: 10 Sheets-Sheet 2 I gmtou, flrlhurmwflhelm, EdwinhRosm y U1 QWMWQW Oct. 5 1937', WILHELMI'ET AL 95 LANDING I NDICATO'R FOR AIRPORTS Filed pla 6. 1931 10 Sheets+$heet5 gwumtou Edw'm hRose,

amid;

flrlhut' m. Wilhelm.

Oct. 5 1937. A. .M. WILHELM El Au 2 5,

LANDING INDICATOR FOR AIRPORTS Filqdjlay 6. 1931 10 Sheets-Sheet 4 v A. M. WILHELM ET AL 2,095,208

LANDING INDICAgfOR FOR AIRPORTS Filed lay e, 1'93: 10 snets-sheet 5 rihurmll ilhelm I Oct. 5, 1937.

A. M. WILHELM ET AL 2,095,208 LANDING INDICATOR FOR AIRPORTS 1 Filed May 6. 19a: 7 1o Sheets-Sheet 7 jwventm Arthur J'lhwihelm, Edwin 1:.R0se,

' Oct. 5, 1937.

AM. WILHELM ET AL LANDING INDICATOR FOR AIRPORTS I Filed May a. 1931 10 Sheets-Sheet 8 rIhurJMlJillwlm EdwinLRose,

A. M. WILHEVLM ET AL 2,095,208

LANDING INDICATOR FOR AIRPORTS w Filed May 6. 1,951 1o Sheets-Sheet 9 66 lz: 7 Jl ihuf lm r u m m EQwinLR Oct. 5, 1937. I M W HEL E AL 2,095,208

LANDING INDICATOR FOR AIRPORTS Filed may 6. 1931 1o Sheets-Sheet 1o a nun 014,

Armurmwilhelm,

BdwinLRose,

. Patented Oct. 5, 1937 v LANDING INDICATOR FOB AIRPORTS ArthurlLWllhclm, Rando ph. N. Y.,andEdwin laidkooealslgnor L. Rose, Cambridge, Mala;

slid Wilhelm Application May 6,1931. Serial No. 535.530

80lalms.

This invention relates to a landing indicator for airports by means of which the flying aviator is apprised of the best direction in which to lanid his aircraft,- safety being the! dominant 5 factor. 4

It is quite customary to use wind socks and freeiypivoting vanes or T's at airports for indicating to the flying aviator the ,direction of the prevailing wind currents and thereby enable l him to land his airplane with greater safety. In

the absence of objectionable wind currents or during calm weather, it may be desirable to land the airplane along a preferred runway, or in a preferred direction, but the flying aviator has no 1 assurance of having such preferred runway or direction indicated to him because of the fact that the wind sock or the freely pivoting T remains in the position in which the dying wind left it, and in fact, with the freely pivoting T, the aviator has no means of ascertaining whether or not a calm is prevailing. Furthermore, to be readily discernible from the air the wind T should be cf'large dimensions but any increase in dimensions is made at a sacrifice of the sensitiveness of the T to the wind currents owing to the weight of the T body.

It is the object-oi the present invention to provide awind T or indicating member, em- OdJ ng appropriate dimensional requirements for being readily discerned from the air, which will be highly sensitive to the wind currents and automatically returned to a predetermined directionalindication in the absence of objectionable wind currents. It is further the object of this invention to provide a sensitive pilot control for the indicating member together with means for maintaining the two substantially in positional agreement, and further, to provide a 6 dependable indicating member upon which-the aviator can rely to designate always the preferred or safest direction for landing his air- I plane in the then prevailing weather conditions.

In the drawings:

45 Fig. 1 isa bird's eye view of an airport depicting one embodiment of our invention.

Fig. 2 is a vertical section through ,the pilot and automatic return controls, parts being left in elevation. to Fig. 3 is a detailed sectional view clarifying the mounting of the pilot member or vane.

Fig. 4 is a detailed section through the mounting of the lower end of the wind wheel shaft. Fig. 5 is a horizontal section about on line H 65 of Fig. 2.

Fig. 6 is a perspective view of the automatic return control switch.

Fig. 7 is a vertical section therethrough illustrating the action of said automatic switch.

Fig. 8 is an elevation of the control panel. 5

'Fig. 9 is a vertical sectionthrough the control panel.

Fig. 10 is an elevation of the base of the control panel with the cover or casing removed.

Fig. 11 is a sectional view about on line li-ll 10 of Fig. 10, with portions left in elevation.

Fig. 12 is a transverse section about on line l2il of Fig. 11, broken away at one side.

Fig. 13 is a fragmentary vertical section through the indicating T and its supporting base. 15 portions being in elevation.

Fig. 14 is a fragmentary sectional view through the base of the indicating T, on an enlarged scale.

Fig. 15 is a detailed view about on line lS-II 20 of Fig. 14. v v

Fig. 16 is a transverse sectional view on line l6--l6 of Fig. 14.

Fig. 1'7 is a fragmentary enlarged view of the cam portion in Fig. 16, depicting the cam closing 2 one of its switches.

Fig. 18.is a plan view of the T-propeiling motor and its brake mechanism.

Fig. 19 is a transverse section on line of Fig. 18. 30

Fig. 20 is a sectional view through the brake mechanism at right angles to the plane of section of Fig. 19. v

Figs. 21 and 22m detailed sectional views on lines 21-41 and 22-42 of Fig. 1a. 35 -Fig.23isawiring diagramofthelandingindicator. v V

In proceeding in accordance with the present invention, the numeral i designates the T or indicating member which is mounted upon a base 2 H for movement about a vertical axis to indicate the direction in which a landing is to be effected.

the heavier it is and the greater is its resistance 5 to the wind currents. To render the indicating T highly responsive to the wind,we providea sen: sitive pilot means which will readily respond to the wind currents, and through this responsive action of said pilot means set in motion mechag TheTis nism for moving the it into positional accord with that of said pilot means.

Such pilot means, in the present disclosure, em bodies a vane 3 pivotally supported by a vertical shaft t and having a tail or vertical fin 5 by which the vane is caused to respond to the wind. This pilot vane may be mounted in a desired posi-- tion best suited for the conditions.

once, we propose to mount the vane upon a tower By preferor other structure by which the vane is disposed in the path of the wind currents unaltered by adjacent buildings about the airport. The vane 3 is connected to a self-synchronous motor 71.

This self-synchronous motor may be termed the transmitter and is electrically interconnected to a similar T-controlling motor 8 which acts as a receiver to reproduce in the T any angular movement which is imparted to the transmitting motor i by the pilot means 3. The self-synchronous motors herein referred to are standard and have their rotors wound with single-phase windings and their stators with three-element or phase, connected windings. Excitation is single-phase and is furnished to the rotor winding. The prin ciple of operation of the self-synchronous motor is well known and needs no elaborate discourse herein.

Therefore, with the transmitter i and the re-' ceiver 3 interconnected to obtain positional accord between the two, any movement of the pilot vane will excite and place the motor 7 out of balance or synchronism with the motor dand thereby cause the latter to reproduce the motion of the motor 7. This reproduced motion is taken advantage of to set in motion the mechanism hereinafter described for bringing the T into positional agreement with the wind-positioned pilot vane.

The pilot vane, being very sensitive to the windcurrents, may whip back and forth in the wind currents and thereby disrupt its positional accord with the T. Such whipping appears to be due to momentary wind variations as distinguished from prolonged or substantial changes in the direction of the wind. To avoid this whip= ping having any influence on the positional relationship between the motors, or varying the position of the T except upon a prolonged change in the wind direction, there is interposed between the pilot vane and the motor 7 a play connection which will accommodate and preferably also yieldably resist the whipping. This connection embodies resilient means which yield to the whipping and which will, in the event that the pilot vane is sustained to one side or the other of its normal with respect to the 1, act to impart the sustained degree of movement to the transmitter and thereby result in a following movement oi the T to restore the positional accord.

In the present disclosure this resilient connection embodies a leaf spring 9 anchored at one end, by a clamp id, to the shaft d and having its opposite end connected to a crank pin it on the arm i2, said arm being connected to the rotor shaft it of the motor yieldable one, permitting the spring 9 to flex to either side ofa normal position. The extent of yieldability may be determined by limit steps 25.

Means'are provided for dampening the action of any sudden movement'of the pilot vane on the rotor shaft 53. This means may consist of a pair of dash pots Hi and it having plungers it, controlled in their movement by bleed valves ii. In the particular showing the plunger-s are connected by their rods id to a crank arm 69 car= This connection is a ried on a shaft 28. Fixed on the shaft is a gear 2! meshing with a second gear 22 which is fixed on the rotor shaft it so that-movement imparted to the rotor shaft by the resilient coupling 9-42 will be dampened by the dash pot action if the imparted movement is of suficient intensity to move the plungers i6 faster than the dashing fluid will permit.

Referring now in particular to the indicating member or T i (Figs. 13 and 1d) the body of said T is supported by a shaft 23 for angular motion about a substantial vertical axis and has such angular motion imparted to it by a suitable power device such as a reversible electric motor 2 3 arranged in the base 2. The motor shaft as car Fixed on the T shaft 23 is a gear 38 meshing with another gear iii carried on the shaft d2 of.

the motor The shaft 32 is journalled in a a bracket 33 from which the receiver 8 is suspended.

The reason for suspending the motor by the shaft 82 is to permit and take advantage of movement of both the rotor and the stator elements oithe same. The term stator with respect to the receiver ii is used for ease in describing and referring to the part which surrounds the rotor and contains the poly-phase windings, and which is usually mounted in a fixed position. Since the receiver is suspended so that the stator may also rotate it is preferred to make the wiring connections with the stator and rotor windings through the brushes 8% and collector rings 35, the latter being insulated by rings 35 and electrically connected to the respective windings as by the wires 31 and The brushes 3% are held in yielding contact with the rings by the brush supporting springs 39 which also conduct the current to the terminal posts 5 8 from which conductors d2 extend to like points on the pilot motor 7 so that like points of the windings oi the two motors are electrically interconnected. The brush and ring contacts enable free movement of the stator element unobstructed by loose wire connections leading from the motor windings.

Since the motor 25 is of the reversible type we provide a double switch under the control of shafts, one is connected to the stator and the other is connected to the rotor of the receiver motor. One shaft suspends the receiver and the other shaft operates thecam disc :2. The cam disc .is interposed between a pair of contact members M and 65 each carrying a roller 66, for riding on the cam 52, and a contact point 67, for circuit-closing engagement with a second con= tact 68 carried by an adjustable contact member 69. Adjustment of member 68 may be ob tained by the screw and slot mounting 5t.

The contact members 44 and 45 preferably are inherently resilient, and may therefore be in the form of leaf springs so as to yieldably hold their rollers 46 in yielding contact with the cam'42. The degree of tension under which the rollers are held may be determined in the mounting of the contact members 44 and 46, and to this end they are each fixed to an anchor member 5| pivotally mounted at 52, the position of the anchor member being adjusted by a set screw 53 engaging the latter at one side of the pivot 52, against a cushioning spring 54 supported against-the anchor member at the opposite side of its pivotal support. Adjustment of the spring tension in the contact members 44 and 45 will vary the pressure of the rollers 46 onthe cam 42 which will, in turn, vary the resistance offered against the turning of the cam, as will now be set forth.

The cam is provided with a shoulder 55 at the base of which the rollers 46 normally rest when the two motors I and 8 are in synchronism or at rest. Now when the self-synchronous motors are excited, as when the wind turns the pilot vane 3 sumcient to turn the rotor of the transmitter I, the receiver 8 will have an urge tending to turn the cam 42 sufliciently to bring the two motors again into positional agreement.

- This tendency of the cam 42 to turn, when of sufpressing the respective spring contact member 44 or 45, depending upon the direction of rotation of the cam) rotates the cam until'arrested by one of. the stops 56 or 51 whereupon the urge holds the respective roller in engagement with its cam stop. In this arrested position the respective contact point 41 is in circuit closing relation with the contact point 48 to thereby close the circuit of the motor 24 so that the latter will rotate in the proper direction to bring the indicating T I into directional accord with the pilot vane 3. When positional agreement is thus established between the indicating T and the pilot vane the two motors I and I will likewise be brought again into balance through the gearing 30, ii, the latterrrotating the stator elementof the motor 8 until the balance is obtained, whereupon the disc 42 will move with the gear 3 I until the shoulder 55 passes from beneath the elevated roller 46. This will break the circuit of the motor 24 through the separation of the heretofore engaged contact points 41 and 48. It will thus be seen that the resistance oflered by the rollers 46 to the turning of the cam'42 will in sheet determine the neutral point a'nd control the degree at which the unbalance relationship between the motors I and 8 is had, and this will also aid indetermining the extent to which the pilot vans. may whip without influencing the indicating T, Adjustment of the set screws 53 will vary this tension or-rolier pressure and the resistance oifered to the receiver 8 reversible motor 24 is connected to the spring contact members 44 and 45, To avoid too much current through the contact points 41 and 4., it is preferred to introduce a relay I! in each of the two circuit wires '2 and I which will serve to close the proper circuit through the reversible motor.

When the two motors I and I are brought into balanced relation or positional agreement a braking mechanism is brought into action to arrest the indicating T against overriding and also to hold the indicating T against any whipping action under the influence of wind currents. This braking mechanism is illustrated particularly in Figs. 18-22, and embodies, according to the present showing, a pair of brake shoes 66 supported by levers 61 and 68 which are in turn pivoted to a supporting bar 69. This bar receives pivotal support from a bracket Hi, and by reason or this mounting the shoes 66 will properly seat upon the periphery of the brake drum 21. A brake applying lever H is pivotally connected to the free end portion of the arm 68 by a pin II and beyond this connection said lever H is connected to the lever or arm 6'! by a rod 13 which passes downwardly through an opening in the lever 61 and carries. adjusting nuts 14 to take up the brake shoesv with respect to the drum. Obviously lifting the long arm of the lever II will remove the brake shoes, from the drum, while a downward movement of said lever II will draw the shoes into braking relation with the drum. An electro-magnet or solenoid I! has its armature I8 pivotally connected to the longer arm of the brake lever ll as indicated at 11, and when the magnet is deenergized the weight of the longer arm together with the weight ofthe armature 16 will provide suflicient pressure to efl'ectively brake the movement of the indicating T and cause the latter to come to rest. When the solenoid is energized its armature will be attracted to lift the adjacent end of the lever II and release the brake. Therefore it is desired to have the solenoid automatically energized with the'closlng of the circuit of the motor 24 and to this end the circuit wires ll of the solenoid I! are connected into this motor circuit. The operation of the landing indicator thus far described is as follows:- 1

Assuming that the pilot vane'and the indicating T are in positional agreement, when a contrary wind impinges upon the vertical plane I of the pilot vaneand turns the latter the spring arm 9 will be placed under tension. If this action is sudden the spring will then urge the arm I! to follow which urge will be momentarily checked or resisted by the dampening action 0! the dash pots l4 and it, This dampening action will gradually become dissipated to permit the arm i! to follow the spring arm 0, thereby moving the rotor of the transmitter I out oi. balance with the receiver I. This positional disagreement results in excitation of the motor 8 to move the respective one of the spring contact members 44 (4!) into circuit closing position whereupon the motor 24 is correspondingly set in action and through the transmission 28 rotary movement is imparted to the indicating T I. This movement will continue until, through the gears 3| and II, the motor I is main brought into balance with the motor] whereupon the cam 42 will release the active springcontact member toiopen the 70 reversible motor circuit and deenergize the solenoid II, whereupon the brake 86 will become effective to arrest the indicating T.

Any whipping of the pilot vane will initially be taken care of through the resiliency of the spring arm 9, as resisted by the dampening action of the dash pots l6 and i5, and then further absorbed by the resistance ofi'ered through the spring contact members id and 35, this resistance occurring when the motors I and 8 are slightly out of balance, but any whipping action whichis taken care of solely by the spring arm 9 does not affect the self-synchronous motors. f

While it is essential, in making a landing, to

bring the airplane down into the wind, the

direction from which the wind was last blowing may not always be the best for landing in the absence of the wind. For instance, airports are provided with various runways-of which one may be preferred over another, when the wind is not the controlling factor, and therefore if there is no substantial wind blowing then it is desirable to inform the aviator of such preferred landing condition. Utmost dependability is obtained by having the indicating T automatically returned to a position for indicating the preferred runway when a calm prevails. Making it automatic ob rdates the human element. The automatic return apparatus will now be described.

Preferably in the control room or ofiice at the airport, is located a control panel (Figs. 8-10) and on this panel is arranged a manual control by which a calm weather landing direction may be readily predetermined and selected. This control embodies a motor 79 to the rotor shaft of which is connected a handle 80 movable over a dial ti and adapted to be secured in a set position by dropping the pin 82 in a selected one of the recesses 83 provided in the dial. Points of the windings of this motor '89 are electrically interconnected tolike points on the receiver motor ii of the indicating T, and thisinterconnection is made through a wind control switch by which the manually set motor 79 is automatically disconnected from the motor 8, in the presence of predetermined wind currents, and is automatically conneced with said motor 8 in the absence of such wind currents. i

This wind controlled switch, according to the present disclosure, embodies a bladed wheel disposed in a position .to be acted on by the I wind currents, as on the tower 5. This wheel is mounted on'a shaft 85, journalled in suitable bearings 86 so as to be sensitive to the wind currents, and the shaft is connected to cooperate with the switch for throwing one of the motors, i! or it out of, and the other into, operative relationship with the motor 8.

In Fig. 6 this switch is shown of the mercury type in which the tube Bl, containing the circuit closing globule of mercury is mounted on a rockable support 88'. One or more of these tubes may be provided, two being herein illustrated to balance the support 88. This support 88 is mounted to rock from an inoperative to an operative position in which latter the circuit between the motors i and 8 is closed and the circuit between the motors i9 and 8 is opened. In the inoperative position the switch opens the transmitter- This shaft also carries a.

aocacoe 99 carried by the wind-wheel shaft 85. The shaft 97 is also provided with a weighted arm me which tends to hold the shaft in its normal or inoperative position. Y

The wind wheel 85 is provided with a pair of spaced stop lugs NH and 102 which are adapted .to engage at difierent times an interposed arresting stop m3. Through the gearing 98 and t9 the weighted arm Hi0 acts to hold the wind wheel 86 in its normally inoperative position in which the stop lug EM is in engagement with the arresting stop M3. In the presence of a wind the wheel 8 will be blown about its vertical axis until arrested by the lug I82. contacting the stop m3 against which the wind will hold said lug, and in this position the weighted arm tilt? is elevated and ready to return the wheel to its normal position when the wind dies down. During this wind actuated movement of the wheel M, and shaft 97, the lug 96 is brought into operative engage-,

ment with the lug to impart pivotal movement thereto sufiicient to bring the weighted arm 93 across the dead center position, which is the vertical plane passing through the longitudinal center of shaft 92. After moving across dead center the weighted arm carries the arm iii quickly along with the shoulder Ed thereby to tilt the support 88 to its operative position in which the mercury switch til closes the circuit through the conductors 8% by which themotor i is electrically connected with the-motor 8 and the mo-' tor i9 is disconnected, in a manner now to be described.

The wind switch 8? is also connected in circuit with a solenoid H35 through the wires Hit, and the armature we of the solenoid is connected to an arm l0! fixed to a shaft we. Fixed on this shaft is a,pair of cams N39 and Hi! having peripheral pockets or recesses Hi to receive lugs H2 carried by spring contact members H3 and lid. The recesses HI on the discfld are staggered or offset relative to those in the periphery of the disc iii] so that in one position of the armature l06 the lugs M2 on the contact members I is will be received within the recesses i i I of their cooperating cam, While the lugs on the contact members M 3 are out of their recesses and are bearing on the periphery of their cam. The cam I09 is disposed between a pair of the contact members H3 and cooperates with each, while the cam H0 is likewise disposed between a pair of contact members H 3 and has like cooperation with each of the latter, so that as the respective lugs H2 are cammed outwardly by the cam Hit contact point H5 carried by each spring contact arm H3 is brought into electrical contact with a like point H6 carried'by an associated contact member HY. During this circuit closing operation between the contact points H5 and 6 like points i IS on the contact arms HA are disengaged from contact points H9 on associated contact members I20. Upon rotation of the shaft ti t in the reverse direction a reverse disposition of the contact points H5, H6 and H7, H8 will take place. I

Conductors Hi and H2 connect the contact members H3 and H? with the stator windings oi the motors 8 and '79, while circuit wires I23 and i243 connect the contact members H 3 and tit in circuit with the stator windings of the motors i and 3. With the wind actuated switch Bl! in a normaliy' inoperative position the motors 8 and it will be electrically interconnected through the closing of the contact points H5 and H 5, and in a prevaiiing wind or sufiicient intensity to render the wind switch operative the contact points H and H6 will be separated to disconnect saidmotors 8 and I9, and the motors I and 8 will be interconnected through the contact points Ill and II 8. V

The intensity of the wind required to actuate the switch 81 is determined by the position to which the weight I25 is adjusted on the arm I00, supplemented by the adjustment of the weight I26 on the arm 93. Therefore when the wind actuated switch 81 is rendered operative the solenoid I05 attracts its armature I06 to impart rotary movement to the shaft I08. The extent of this rotary movement is determined by a stop I2! on the armature, designed to abut a fixed part of the solenoid. When the wind dies down below the predetermined velocity, sufilcient to cause the weight I25 to restore the switch 81 to an inoperative position, the solenoid I05 will become deenergized and the shaftwill be given an opposite turn through the weight of the arm I28 which is also fixed to the shaft I08. This return movement is dampened and retarded by a dash pot. I29. A weighted arm I30, also fixed to the shaft I08, may be provided to control this movement. A stop I3I can be provided to limit the return movement.

A telltale self-synchronous motor I32 may be provided on the control panel I33 in the operating room with its rotor shaft carrying a pointer I34 for operating over a dial I35, and this telltale motor I32 is electrically interconnected with the receiver 8 so as to indicate on the dial the position of the T. The motor I32 is preferably connected permanently with respect to the T motor 8 so that the pointer I34 will always indicate the position of the indicating T whether the latter is in circuit with either the pilot motor or the manually set motor.

The control panel may also be equipped with the main current supply switch I35 and a manual throw switch I36, the latter being interposed in the circuit to permit the manual throwing in and out of the motors I and I9 with respect to the T motor 8. By this arrangement the T may be rendered solely manual or solely automatic in action.

The control panel is herein illustrated as comprising .a base I50 and a cover I5I mounted thereon, as by means of hinges I52. The cover is preferably in the form of a hollow casing so that when it is closed against the base the two cooperate to enclose the parts carried by the control panel. The automatic switch actuated by the solenoid I05 may be mounted directly on the base I50 along with the main switch I35 and the manual throw switch I36. In Fig. the base is also equipped with fuse connections I53 for inclusion in the main incoming circuit wires. The several conductors of the .apparatus may be conveniently connected through the bus bars I54. The motors I9 and I32 are supported by brackets I55 within the cover I5I, with their rotor shafts projecting through-the front wall of the cover to support the handle 80 and the pointer I34, respectively.

The pilot arrangement upon the tower 6 is in a compact assembly, with the pilot motor I and the wind actuated switch mechanism, excepting the wind wheel 84, enclosed by a casing I31 upon the platform I38. Suitable standards or frame members I39 are carried by the platform I38 to sup- I port the wind actuated switch structure and pro-' vide journal bearings for the shafts thereof as W as pp Q3! 9? 2 31? 85 The lower bearing 86 is'conveniently carried by means of astrap support I40 so as to provide ample exposure of the wheel 84 to the wind currents, the tower 6 being of skeleton frame formation for similar reasons.

For night use the indicating T I is illuminated as by means of a'series of incandescent bulbs, and to render the same more efllcient it is preferred to provide the illumination in warning" and switches I48 and I49 which selectively control the illumination of the red and green series of lights.

In operation, and assuming the throw switch I36 is connecting the indicator for automatic operation, any sustained change in position of the pilot-vane by the wind of predetermined velocity will excite the motor I until the indicating T is propelled by its drive into substantial positional agreement with the vane. During this actuation the wind wheel 84 is held'in a position to render the switch 8! operative and thereby electrically connect the motors I and 8 and disconnect the motor I9 from motor 8. As the wind dies down and the wheel 84 returns to render the switch 81 inoperative with respect to the pilot motor I, the latter will be electrically disconnected from the T motor 8 and the two motors 8 and I9 will be electrically connected with one another' whereupon, when at this moment there is positional disagreement between the motors I9 and 8, the T motor will set in motion the T-moving mechanism so as to bring the T into positional agreement with the indicator or handle '80 at which time the solenoid 15 will becomadeenergized and permit application of the brake 66 to arrest and hold the T in such position. At all times, the telltale motor I32 will display, through the pointer I34, the position of the T. Therefore, the T will always return to a position as predetermined by the manually set motor I9 in the absence of any objectional wind currents.

Obviously if the automatic feature is not desired the throw switch I38 may be manipulated to render the T purely of manual control. With the present invention we are enabled to provide a T of appropriate dimensions to be readily observed from the air and at the same tin e be highly sensitive to the prevailing wind currents through the pilot control.

The calm weather is referred to as including conditions in which the wind velocity is insumcient to actuate the drive for the indicating T. The degree of wind velocity required to set the T mechanism in motion isdetermined by the resiliency of the spring-9 either solely or jointly with the adjustment of the spring contact members which cooperate with the cam 42. Obviously either one of these two play connections may be used independently of the other to vary the resistance oflered to the T-moving mechanism. The self-synchronous motor herein referred to is of the type generally found in the trade under the name Selsyn", and acts in establishing and sented by the reference characters PI and P2;-

' the conductors connecting the rotors of the selfsynchronous motors by RI and R2; and the conductors connecting the stator elements of the several self-synchronous motors by the reference characters SI, S2 and S3 by which characters the corresponding points in the stator windings are also designated.

Assuming that there is no wind'and the solenoid I05 is deenergized while the double throw switch I36 is in its automatic position, the circuit is then through contact fingers H3 and Ill, conductors Ill and I22 through their wires SI and S3 to the manually set motor I9 and to the T motor 8. The telltale motor I32 is always in connection with the T motor.

When the wind rotates the pilot 3 and excites the pilot motor I the wind wheel 84 will also close the switch 81 to energize the solenoid I05 and thereby break the circuit through the contact fingers I I3 and Ill and close the automatic circuit through the contact fingers H4 and I211. The circuit will. then trace from the pilot motor 1 along wires SI and S3 (I24), thence through contact fingers I20 and H4, through conductors I23 to the automatic side of the double throw switch I36 and from thence through wires SI and S3 to the telltale motor I32 and the T motor 8, cutting the manually set motor 19 out of service.

Now, when the double throw switch I36 is shifted to the manual side, the entire system is then to the T motor 8 and the telltale motor I32,

thus, in effect, paralleling the contact fingers H3 and II! when the latter are connected. The direction of rotation of any particular receiving motor may be reversed by reversing its conductors SI and S3. For instance, the T motor 8-is shown as having its leads SI and S3 reversed. This reversal will, through the gears 30 and 3!, provide for corresponding movements in the pilot and T and maintain the desired positional agreement therebetween. Obviously, the T could ,be disposed directly on the rotor shaft of a fixed self-synchronous motor and accomplishpositional accord with the pilot. Such an arrangement would eliminate the necessity of special drive mechanism for the T but would also probably require a heavier self-synchronous motor with an increased consumption in current. This arrangement embodies the spirit and conceptof the present invention.

What is claimed is: k

l. A landing indicator for airports comprising a relatively heavy rotatable wind direction indicator, pilot means directionally responsive to windcurrents, actuating means for moving the indicator to indicate the landing direction, means controlled by the pilot means to cooperate with said actuating means for maintaining positional agreement between the pilot means and indicator when the pilot controlled means is operatively related to said actuating means, preselective means'for efiecting operation of the actuating means for moving the indicator to a predeterwiring dia- I tending to maintain the parts of the indicator mined position when said pilot controlled means and said actuating means are not operatively related, and wind actuated means normally inoperative but operable by a wind greater than a predetermined velocity for establishing an operative relation between the actuating means and said pilot controlled means, said wind-actuated means embodying means for disrupting the operative relationship between said preselective means and said actuating means when the pilot controlled means is operatively related to the actuating means.

2. A landing indicator for a1rports comprising a relatively heavy ,wind' direction indicating member, a pilot responsive to wind currents, electrically actuated means for moving the indicating member into positional agreement with the pilot, manually set means for operating said first means to bring the indicating member into a predetermined position, means under the control of the pilot 'for controlling the first means to maintain such positional agreement between the pilot and the indicating member, said first means being adapted for connection in electric circuit with said manually set means and with. said pilot controlled means, and a wind actuated switch connecting the first means to the manually set means when the wind is below a presaid first means into electric circuit, with said pilot controlled means to the exclusion of saidmanually set means, whereby said first means will position said wind indicating member in accordance with the said positioned pilot.

1 3. A landing indicator for airports, comprising a relatively heavy wind direction indicating member, a pilot responsive to wind currents, electric means for moving the indicating member into positional agreement with the pilot, means underthe control of the pilot for controlling the first means to maintain such positional accord between the pilot and the indicating member, said pilot controlled means adapted for electric circuit connection with said first means, a manually set means normally in circuit connection with said first means for causing the indicating member to assume a predetermined position in the-absence of predetermined wind currents, and wind responsive means operable by such predetermined wind currents for electrically connecting the first means to said pilot controlled means to the exclusion of said manually set means whereby the indicating member is caused to fol-' low the pilot in positional agreement therewith. 1 4. A landing indicator for airports, comprisin determined velocity and operable by a wind 7 above such predetermined velocity for bringing a relatively heavy wind direction indicating memher, a pilot responsive to wind currents, electric means for moving the indicating member into positional agreement with the pilot, means under the control of the pilot for controlling-the first means to maintain such positional accord between the pilot and the indicating member, said pilot controlledmeans adapted for electric circuit consaid manually set means, and a wind actuated member operable by such predetermined wind currents for actuating said switch and having a connection therewith permitting of a preliminary movement ineffective on the switch in the absence of such predetermined wind currents.

5. A landing indicator for airports, comprising tween the pilot and the indicating member, said pilot controlled means adapted for electric circuit connection with said first means, a manually set means normally in circuit connection with said first means forcausing the indicating member to assume a predetermined position inthe absence of predetermined wind currents, a switch for bringing the first means into electric circuit with the pilot controlled means to the exclusion of said manually set means, a wind actuated member operable by ,such predetermined wind currents for so actuating the switch, and means for insuring a closing of the switch upon a predetermined actuation by said wind actuated member.

6. A landing indicator for airports, comprising a relatively heavy wind direction indicating member, a pilot responsive to wind currents, electric means for moving the indicating member into positional agreement with the pilot, means under the control of the pilot for controlling the first means to maintain such positional accord between the pilot and the indicating member, said pilot controlled means adapted for electric circuit connection with said first means, a manually set means normally in circuit connection with said firstmeans for causing the indicating member to assume a predetermined position in the absence of predetermined wind currents, wind responsive means operable by such predetermined wind current for electrically connecting the first means to said pilot controlled means to the exclusion oi said manually set means whereby the indicating member is caused to follow the pilot in positional agreement, therewith, and a telltale indicator accessible when operating the manually controlled means and operatively connected to the indicating member for indicating the position of the latter when in circuit with both the pilot controlled means as well asthe manually set means.

7. Alanding indicator for airports, comprising a relativelyheavy wind direction indicating member, a pilot responsive to wind currents, electric means for moving the indicating member into positional agreement with the pilot, means under the control of the pilot for controlling the first means to maintain such positional accord between the pilot and the indicating member, said pilot controlled means adapted for electric circuit connection with said first means, a manually set means normally in circuit connection with said first means for causing the indicating. member to assume apredetermined position in the absence of predetermined wind currents, wind responsive means operable by such predetermined wind currents for electrically connecting the first means to said pilot controlled means to the exclusion of said manually set means whereby the indicating member is caused to follow the pilot in positional agreement therewith, and selective means operable to render either the pilot controlled means or the manually set means wholly ineffective manual or whollyautomatic in action.

8. A landing indicator for airports comprising a relatively heavy rotatable wind direction indicator, pilot means directionally responsive to wind currents, actuating means for moving the indicator to indicate the landing direction, means controlled by the pilot means to cooperate with said actuating means for maintaining positional agreement between the pilot means and indicator when the pilot controlled means isoperatively related to said actuating means, preselective -means for efiecting operation of the actuating means for moving the iridicator to a predetermined position when said pilot controlled means and said actuating means are not operatively related, and wind actuatedmeans normally inoperative but operable by a wind greater than a predetermined velocity for establishing an operative relation between the actuating means and said pilot controlled means, said wind actuated means having the initial idling movement for a wind less than such predetermined velocity embodying means for disrupting the operative relationship between said preselective means and said actuating means when the pilot controlled means is operatively related to'the actuating means.

EDWIN L. ROSE. 

